1. Field of the Invention
The present invention relates to liquid surface level sensing devices and, more particularly, to an apparatus for sensing a liquid surface level reaching a predetermined height by means of using the electric conductivity of the fluid.
2. Description of the Prior Art
Heretofore, numerous apparatuses and devices have been employed for detecting the level of a liquid. Examples of such devices are disclosed in United States Letters Patents No. 1,055,099; No. 3,374,764; No. 3,680,579; and No. 3,817,274. These patents are relevant to the present invention in that they relate to indicators and alarms for indicating the height of a fluid, such as water, in tanks, vessels, and the like and for automatically sounding an alarm when a predetermined level has been reached. A particularly known problem is that associated with the flooding of basements within buildings. To the knowledge of the inventors, no known device has been made which is used within this environment and which is commercially available. The use of the devices in the aforementioned patents as applied to the basement environment falls short of some of the criteria desired for having an alarm in this environment. In the aforementioned patents, the devices disclosed would find use only after the basement has actually been flooded. It would therefore be desirable to provide a device and system for using the same wherein the occupants of the building may be advised in advance of the commencement of a flooding condition so that the occupants may be able to take sufficient action to minimize damages and/or prevent actual flooding from occurring.
Additionally, none of the prior art suggests the concept of utilizing the conductivity of the liquid itself to activate the alarm and thereby eliminate the necessity for moving parts, which are necessary elements of the devices disclosed in the aformentioned patents.
3. Prior Art Statement
The prior art listed hereinabove, in the opinion of the applicants, is the closest prior art of which the applicants are aware.